To verify the Starlab Mission's optical requirements for a pressurized module window, a program with a series of specialized optical tests was required. In this paper a brief description of each optical test will be defined along with the description of the Spacelab Optical Viewport (SOV) glass assembly. The glass assembly is a window installed in the aft end cone of the Spacelab module. It has been designed to act as a structural member in the module shell and also to provide a path through which radiation can pass. The optical test definition will include the test requirements, test description, and test results. A transmitted wavefront and transmission test was conducted to verify the wavefront error and glass coating quality respectively. A Bidirectional Reflectance-Distribution Function (BRDF) measurement was taken to determine the outgassing effects of the window's non-metalic components and cleanliness level of the glass from assembly to installation in module. The optical performance of the assembled unit was verified by performing a wavefront and dispersion test at ambient conditions and wavefront test under simulated space flight pressure. This test program satisfies Marshall Space Flight Center (MSFC) requirements for optical space flight hardware. The SOV glass assembly design has gone through preliminary design review, critical design review, and has been fabricated, assembled and tested.